Determination of the magnetic phase diagram in the H-T plane for a sigma-phase Fe47Mo53 alloy: Double re-entrant transition

Abstract

Abstract Magnetization measurements were carried out in the in field-cooled (FC) and in zero-field-cooled (ZFC) conditions versus temperature, T, and external magnetic field, H, on a sigma-phase Fe47Mo53 compound. Analysis of the measured MFC and MZFC curves yielded values of characteristic temperatures: magnetic ordering (Curie) temperature, TC, irreversibility temperature, Tir, temperature of the maximum in MZFC, Tm, identified as the Nėel (TN) temperature, and cross-over temperature, Tco. Based on these temperatures a magnetic phase diagram in the H-T plane was outlined. The field dependences of the characteristic temperatures viz. of the irreversibility and of the cross-over temperatures were described in terms of a power law with the exponent 0.5(1). In the whole range of H i.e. up to 800 Oe, except the one H\u202f≤\u202f50 Oe, a rare double re-entrant transition viz. PM\u202f→\u202fFM\u202f→\u202fAF\u202f→\u202fSG takes place. For small fields i.e. H\u202f≤\u202f50 Oe a single re-entrant transition viz. PM\u202f→\u202fFM\u202f→\u202fSG is revealed.